1. Field of the Invention
The present invention relates to a nozzle and more particularly, to a nozzle having a self-cleaning function of automatically discharging foreign matter which has collected in a fluid path of the nozzle. The nozzle is preferably used to clean a paper making machine because many solid bodies are present in the liquid or fluid used for cleaning. The nozzle is also used as an acid wash nozzle for an iron manufacturing machine.
2. Description of the Related Art
Conventionally, there have been proposed a self-cleaning nozzles as shown in FIG. 28 which automatically discharge foreign matter which has collected in the interior thereof by reducing atomization pressure during a self-cleaning operation.
According to the above-described self-cleaning nozzle, a spray button 3 having a groove 2 formed thereon is fixed to the leading end portion of a nozzle main body 1, a piston 5 slidably provided in the main body 1 is urged by a spring 4 in the direction opposite to the spray button 3, and the end portion of the piston 5 opposite to the spray button 3 is sealed with a flexible diaphragm 6.
In an atomizing operation, the piston 5 is pressed against the spray button 3 against the resilience of the spring 4 by the atomization pressure of liquid or fluid which has been introduced into the nozzle in the direction shown by an arrow (A) (axial direction of nozzle) of FIG. 29, and an injection opening 7 consisting of a slit-shaped orifice is formed by the groove 2 and the leading end of the piston 5 so as to spray liquid or fluid in the direction shown by the arrow (B) approximately perpendicular to the direction shown by the arrow (A).
If foreign matter has collected in the above nozzle and liquid or fluid is prevented from flowing, the atomization pressure is reduced so that the piston 5 is moved backward or to the original position by the spring 4 so as to return the state of the nozzle to the original state as shown in FIG. 28. Thus, the injection opening 7 is opened and as a result, the foreign matter is discharged.
However, according to the above self-cleaning nozzle 11, the injection opening 7 consists of a thin slit-shaped orifice, i.e. the diameter of the path for the flow of liquid or fluid is small. Therefore, compared with other fan-shaped nozzles, foreign matter is likely to collect in the injection opening 7 when a spray operation is performed.
With to the nozzle 11, the liquid introducing direction (direction shown by the arrow (A)) is approximately perpendicular to the atomization direction (direction shown by the arrow (B)). When the nozzle 11 is used by mounting it on a pipe 10 as shown in FIG. 30, the following problems occur.
That is, when the injection opening 7 mounted on the pipe 10 is pointed vertically downwardly as shown in FIGS. 31 and 32, the atomization distribution 12 and the atomization region 13 are symmetrical with respect to the nozzle 11 as shown in FIG. 33. But when the injection opening 7 is not pointed vertically downwardly as shown in FIGS. 34 and 35, the atomization region 13 is dislocated as shown in FIG. 36 and the atomization distribution 12 is not symmetrical with respect to the nozzle 11.
In addition, when a plurality of the nozzles 11 are mounted on the pipe 10 spaced from one another at regular intervals to spray liquid to cover a long distance as shown in FIG. 37, atomization patterns 14 of the adjacent nozzles 11 overlap with each other, with the result that atomized liquid from one nozzle interferes with that from neighboring nozzles, as denoted by reference symbol 15.
Since the atomization distribution 12 and the atomization region 13 are not symmetrical with respect to the nozzle 11 and the interference 15 of atomization pattern is likely to occur, it is necessary for the nozzle 11 to be positioned accurately. Therefore, as shown in FIG. 30, a parallel threaded portion 16 is provided on the periphery of the nozzle 11 so as to mount the nozzle 11 on the pipe 10 by tightening the parallel threaded portion 16 into threads formed at the surface 10a of the pipe 10. The mounting mechanism requires a lock nut 17 for accurate positioning and an O-ring 18 for preventing liquid leakage. Further, it is necessary to flatten the mounting surface 10a by flattening the nozzle mounting position of the pipe 10. As described above, according to the conventional nozzle, the number of parts and piping processes increases and moreover, labor for mounting parts on the pipe increases.